Sound-record tablet.



No. 809,263. PATENTED JAN. 2, 1906. W. H. HOYT & W. J. GAVEN.

SOUND RECORD TABLET.

APPLICATION FILED JUNE 15, 1905.

III- I 1 III/III! Qnuenfow UNITED STATES PATENT OFFICE.

CONNECTICUT, ASSIGNORS I TO THE NEW JERSEY, A CORPORATION BURT COMPANY, OF HACKENSACK,

OF NEW JERSEY.

' SOUND-RECORD TABLET.

Specification of Letters Patent.

Patented Jan. 2, 1906.

Original application filed June 11, 1904, aerial No. 212,216. Divided and this application filed June 15, 1905. Serial No. 265.325.

To all whom it may concern:

Be it known that we, WILLIAM HELM HOYT and WILLIAM JOSEPH GAVEN, of Bridgeport, Connecticut, have invented a new and useful Improvement in Sound-Record Tablets, which invention is fully set forth in the following specification.

This invention has reference to pressed or molded sound recordsthat is to say, of sound-records which are made by impressing the undulations corresponding to soundwaves upon a suitable tablet in the form of a I disk, cylinder, or other suitable form.

Heretofore pressed or molded records have generally been formed upon tablets of homogeneous material having the same coeflicient of expansion and contraction throughout their mass. For this purpose various materials or compositions have been used with commercially satisfactory results. For making cylindrical records compositions of a wax like character have been most commonly used. For making disk records compositions of earthy material compacted under pressure by means of a suitable binder, such as schellac, have been commonly used. These articles must have a mass or thickness sufficient to give them the strength required to withstand the incidents of handling and transportation, and in order to reduce the cost it has been proposed to make the body of the tablet of a relatively cheap substance (such as pasteboard or papier-mach) and to spread thereupon a surface of the sound-recording composition. In such cases, however, the inconveniences arising from tablets composed of two substances differing in respect of their coefficient of expansion have prevented the lasting or successful use thereof. Records have also been made of a very thin shell of celluloid, xylonite, and like materials backed up by a thicker shell of pasteboard or the like without causing the adjacent surfaces of the two materials to adhere, so that each can expand and contract at its own natural rate.

The present invention has for its object to reduce the cost of the production of soundrecords without any injurious effect upon the quality of the surface and without sacrifice of the strength of the tablet and without incurring the objections which exist in composite tablets.

The invention is applicable to compositions which are for all practical purposes h0- mogeneous throughout, but which contain an ingredient whose presence is necessary to give to the surface the hard glazed finish and other qualities absolutely indispensable for proper sound-reproduction. For example, in the compositions of earthy material now commonly employed in the production of disk records an ingredient such as shellac is necessary to give the proper finish to the surface. This ingredient serves also as a binder and in making these compositions (whether for sound-records or other purposes) has always been distributed uniformly throughout the mass. This ingredient will be herein termed the glaze.

Specifically, we have discovered that a pressed sound-record formed of earthy material and containing the glaze only on the surfacethat is to say, in a relatively small part of the entire thickness of the tabletthe body of the tablet being formed of a similar composition containing an ordinary binder, has not only all the acoustical qualities of the sound-records as now made, but practically the same strength and resistance to shock and the same coefficient of expansion and contraction throughout its mass. Inasmuch as the glaze is the expensive ingredient in the composition, the invention materially diminishes the cost of production of these articles.

The invention may be applied in various ways. Practically we have found the follow ing process to give good results, and it constitutes the best way in which we have contemplated applying the principle of the said invention: We form two batches of the plastic composition. One of these contains the usual ingredients mixed with an ordinary binder, such as Manila gum. The other contains the same (or like) ingredients, with shellac instead of Manila gum. The two batches are rolled into sheets, that which is to form the surface of the tablet being quite thin relatively to the thickness of the sheet which is to form the body of the tablet. These two sheets when heated unite strongly together. The combined sheet is used as in the ordinary process of pressing records, the side containing the glaze being applied to the matrix. The pressure impresses the soundrecord herein disclosed is not claimed in the record upon the tablet and compacts the} Whole into what is practically a homogeneous 1 tablet. A great many plastic compositions of the kind referred to herein are in common use, and the preparation thereof is well understood. Such composition may be formed of terra alba, ten parts; barytes, ten parts, and flock, four parts, (by weight,) with Manila gum for the ordinary stock and shellac for the surface stock. A suitable pigment may be added.

For the purpose of illustration there is shown in the accompanying drawing a sectional view through a flat or disk type of sound-record such as heretofore described.

Referring to the drawing, 1 indicates the body of the tablet, formed of a suitable earthy material and containing any usual or suitable binder, such as Manila gum, and 2 indicates the surface of the tablet in which the record of sound is formed and which is composed largely of a suitable glaze, such as shellac, which, however, forms only a relatively small part of the entire thickness of the tablet. In the drawing the thickness of the skin in proportion to that of the body is exaggerated for clearness of illustration.

The novel process of making the soundpresent application, since such process forms the subject of our application, Serial No.

212,216, filed June 11, 1904, of which the present application is a division.

What is claimed is 1. A sound-record tablet whose body is composed mainly of earthy material and having a thin surface layer composed of like earthy materials with the addition of shellac.

2. A sound-record consisting of a tablet of suitable earthy materials containing little or no shellac but provided with a skin containing shellac and containing also resisting material similar to that of the body of the tablet, having the sound-record in or upon said s rm.

3. A sound-record consisting of a tablet having a uniform coefficient of expansion whose body is composed mainly of earthy materials containing little or no shellac and having a surface layer containing like earthy materials and shellac, said layers being united together and constituting a tablet, the s0und-record groove being impressed upon said surface layer.

In testimony whereof we have signed this specification in the presence of two subscribing witnesses.

VVILLlAM HELM HOYT. WVILLIAM JOSEPH GAVEN.

Witnesses:

JOSEPH HENRY WHEELER. HARRY G. BRISTOL. 

